Optical device and image display apparatus

ABSTRACT

An optical device includes: an optical portion that has a light incident surface on which light is incident; a movable portion that supports the optical portion; a shaft portion that supports the movable portion so that the movable portion is oscillatable; and a fixing portion that is connected to the shaft portion, wherein the fixing portion has a thickness greater than the shaft portion and includes a portion of which an end not connected to the shaft portion serves as a free end.

BACKGROUND

1. Technical Field

The present invention relates to an optical device and an image displayapparatus.

2. Related Art

Projectors and head-mounted displays are known as projection type imagedisplay apparatuses in which images are generated by controlling thewavelength or intensity of light for each pixel in image formingelements including two-dimensionally arrayed pixels and the images areexpanded and displayed by optical systems such as lenses. Liquid crystalelements or organic EL elements are used as the image forming elementsand the resolutions of these elements are designed to be improved everyyear.

At present, in markets of image display apparatuses, products withresolutions called full high-visions have been spread. In future, theseproducts are expected to migrate to, for example, products with highresolutions called 4K or 8K (super high-visions).

As one of the methods of realizing such high-resolution display, thereis a method of using a pixel shift device (pixel shifter) shifting aprojection position of an image generated by an image forming element.As the pixel shift device, a device shifting an optical path usingrefraction (optical modulation) in an optical element is known.

For example, JP-A-2009-171784 discloses an oscillation driving devicethat includes a flap in which a glass transmitting projection light ofan image forming apparatus, a coil, and a belt-like plate spring bent bya propulsion force generated in the coil and generating a reactive forceare fitted. The belt-like plate spring includes a twisting beam portionand supports the flap so that the flap can be oscillated. The twistingbeam portion is connected to a bending beam portion formed to bevertical to an oscillation axis center. In the oscillation drivingdevice, when a current flows in the coil, a propulsion force isgenerated and the flap in which the glass is fitted is oscillatedagainst a spring reactive force of the belt-like plate spring. Byoscillating the glass in this way, it is possible to shift a projectionposition of the light transmitted through the glass.

However, in such an oscillation driving device, the belt-like platespring which is spread in a planar shape and for which a given area isnecessary is used to oscillate the flap. Therefore, there is a problemthat it is difficult to decrease an occupation area of the device.

On the other hand, in order to decrease the occupation area, a bendingbeam portion formed to be vertical to the oscillation axis center can beconsidered to be omitted in the oscillation driving device disclosed inJP-A-2009-171784. In this case, however, since it is necessary tooscillate the twisting beam portion, it is necessary to lengthen thelength of the twisting beam portion sufficiently in order to obtain apredetermined oscillation frequency while sufficiently decreasinggenerated stress. Consequently, the twisting beam portion may belengthened.

SUMMARY

An advantage of some aspects of the invention is that it provides anoptical device which is miniature and in which generated stress is smalland an image display apparatus which includes the optical device and iscapable of realizing high quality display.

Such an advantage can be attained by the following configurations.

An optical device according to an aspect of the invention includes: anoptical portion that has a light incident surface on which light isincident; a movable portion that supports the optical portion; a shaftportion that supports the movable portion so that the movable portion isoscillatable; and a fixing portion that is connected to the shaftportion. The fixing portion has a thickness greater than the shaftportion and includes a portion of which an end not connected to theshaft portion serves as a free end.

With this configuration, since the fixing portion has not only thefunction of supporting the shaft portion but also the function of a beamoscillating the movable portion, it is possible to obtain the opticaldevice which is miniature and in which stress generated at the time ofoscillation of the movable portion is small.

It is preferable that the optical device according to the aspect of theinvention further includes a permanent magnet that is provided in themovable portion; and a coil that generates a magnetic field to beoperated to the permanent magnet.

With this configuration, the magnetic interaction is generated betweenthe permanent magnet and the coil, and thus it is possible to generate adriving force to the permanent magnet.

It is preferable that the optical device according to the aspect of theinvention further includes a support portion that supports the fixingportion, and the support portion supports the fixing portion at aposition at which the portion serving as the free end is excluded.

With this configuration, the portion serving as the free end isprevented from being directly supported by the support portion, and thusthis portion can be displaced with a sufficient displacement amount. Asa result, it is possible to oscillate the movable portion at a necessaryoscillation angle without causing local stress concentration.

In the optical device according to the aspect of the invention, it ispreferable that an elastic modulus of each of the movable portion, theshaft portion, and the fixing portion is smaller than an elastic modulusof the optical portion.

With this configuration, a twistable property (a nature in which theshaft portions can be twisted) is given to the shaft portion and aflexible property (a nature in which the fixing portions are flexible)is given to the fixing portions. Further, a function of suppressingdeformation and precisely transferring a driving force generated by thedriving portion to the entire movable portion is given to the opticalportion. Therefore, a displacement amount at the time of the oscillationof the movable portion is stabilized, and thus it is possible to deflectlight transmitted through the optical portion in a target deflectiondirection or by a target amount.

In the optical device according to the aspect of the invention, it ispreferable that each of the movable portion, the shaft portion, and thefixing portion is formed of a resin material.

With this configuration, a twistable property (a nature in which theshaft portions can be twisted) is given to the shaft portion and aflexible property (a nature in which the fixing portions are flexible)is given to the fixing portions. Further, a function of suppressingdeformation and precisely transferring a driving force generated by thedriving portion to the entire movable portion is given to the opticalportion. Therefore, a displacement amount at the time of the oscillationof the movable portion is stabilized, and thus it is possible to deflectlight transmitted through the optical portion in a target deflectiondirection or by a target amount. Since a resin material has relativelylarge elasticity, the resin material contributes to attenuation ofunnecessary vibration occurring in the optical portion due to theoscillation. Thus, it is possible to prevent the light deflected by theoptical portion from being deflected in an unintended direction.

In the optical device according to the aspect of the invention, it ispreferable that, in the fixing portion, a thickness of a portionconnected to the shaft portion is thicker than a thickness of a portionmutually adjacent to the portion connected to the shaft portion.

With this configuration, the portion connected to the shaft portion isthe portion serving as the free end. Therefore, by thickening thethickness of this portion, it is possible to secure relatively largedisplacement amount when the portion is displaced. Therefore, thisportion can be displaced more considerably, and thus an alleviationwidth of stress occurring inside the fixing portion can be accordinglyfurther enlarged. Further, the oscillation angle can be sufficientlyenlarged.

In the optical device according to the aspect of the invention, it ispreferable that the optical portion transmits light.

With this configuration, by changing the posture of the optical portionso that the incident angle of the light incident on the optical portionbecomes a target angle, it is possible to control a deflection directionor a deflection amount of the transmitted light.

In the optical device according to the aspect of the invention, it ispreferable that the optical portion reflects light.

With this configuration, by changing the posture of the optical portionso that the incident angle of the light incident on the optical portionbecomes a target angle, it is possible to control a deflection directionor a deflection amount of the reflected light.

An image display apparatus according to another aspect of the inventionincludes the optical device according to the aspect of the invention.

With this configuration, it is possible to obtain the image displayapparatus which is miniature and has high reliability.

In the image display apparatus according to the aspect of the invention,it is preferable that a position of a pixel displayed by radiating thelight is shifted by changing an optical path of light exiting from theoptical device in the optical device.

With this configuration, for example, a high resolution of the projectedimage can be achieved without increasing the number of pixels of theimage formed by the light incident on the optical portion.

In the image display apparatus according to the aspect of the invention,it is preferable that the optical device allows the light to scan toform an image.

With this configuration, it is possible to achieve the high resolutionof the projected image.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described with reference to the accompanyingdrawings, wherein like numbers reference like elements.

FIG. 1 is a diagram illustrating an optical configuration of a projectorto which a first embodiment of an image display apparatus according tothe invention is applied.

FIG. 2 is a block diagram illustrating an electric configuration of theprojector illustrated in FIG. 1.

FIG. 3 is a perspective view illustrating the configuration of anoptical path deflection element (first embodiment of an optical deviceaccording to the invention) illustrated in FIG. 1.

FIG. 4 is an enlarged perspective view illustrating the periphery offunctional portions and a driving portion in the optical path deflectionelement illustrated in FIG. 3.

FIG. 5 is a plan view illustrating the functional portions illustratedin FIG. 4.

FIG. 6 is a partially enlarged perspective view illustrating thefunctional portions illustrated in FIG. 4.

FIG. 7 is a partially enlarged perspective view illustrating thefunctional portions illustrated in FIG. 4 when viewed from the frontsurface side.

FIG. 8 is a cut sectional view illustrating the functional portions whencut along an oscillation axis A of FIG. 7.

FIG. 9 is a diagram illustrating a simulation of a displacement statewhen the functional portions illustrated in FIG. 4 are oscillated aboutthe oscillation axis A.

FIG. 10 is a diagram illustrating the simulation of the displacementstate when the functional portions illustrated in FIG. 4 are oscillatedabout the oscillation axis A.

FIGS. 11A and 11B are diagrams illustrating a configuration example of adriving portion according to the first embodiment.

FIGS. 11C to 11H are diagrams illustrating other configuration examplesof a driving portion in which an electromagnetic actuator scheme isadopted.

FIG. 12 is a diagram illustrating a principle in which the optical pathdeflection element illustrated in FIG. 3 deflects light.

FIG. 13 is a diagram illustrating the principle in which the opticalpath deflection element illustrated in FIG. 3 deflects light.

FIG. 14 is a diagram illustrating a principle in which an optical pathdeflection element to which a second embodiment of the optical deviceaccording to the invention is applied deflects light.

FIG. 15 is a diagram illustrating an optical configuration of aprojector to which a third embodiment of an image display apparatusaccording to the invention is applied.

FIG. 16 is a perspective view illustrating a head-mounted display towhich a fourth embodiment of the image display apparatus according tothe invention is applied.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

Hereinafter, an optical device and an image display apparatus will bedescribed in detail according to preferred embodiments illustrated inthe appended drawings.

First Embodiment

Projector

An optical path deflection element to which a first embodiment of theoptical device according to the invention is applied and a projector towhich the first embodiment of the image display apparatus according tothe invention is applied will be described.

FIG. 1 is a diagram illustrating an optical configuration of a projectorto which the first embodiment of the image display apparatus accordingto the invention is applied. FIG. 2 is a block diagram illustrating anelectric configuration of the projector illustrated in FIG. 1. FIG. 3 isa diagram illustrating the configuration of the optical path deflectionelement (the first embodiment of the optical device according to theinvention) illustrated in FIG. 1. FIG. 4 is an enlarged perspective viewillustrating the periphery of functional portions and a driving portionin the optical path deflection element illustrated in FIG. 3. FIG. 5 isa plan view illustrating the functional portions illustrated in FIG. 4.In the following description, in the optical path deflection element, asurface illustrated in FIG. 5, that is, a surface on which a drivingportion is mounted is referred to as a “rear surface” and an oppositesurface to the surface is referred to as a “front surface (outersurface)” to facilitate the description. In FIG. 5, a part of thedriving portion is not illustrated.

A projector 1 illustrated in FIG. 1 is a projection type projector thatenlarges and projects an image displayed in a liquid crystal element.

As illustrated in FIG. 1, the projector 1 according to the embodimentincludes a light source 102, three mirrors 104 a, 104 b, and 104 c, twodichroic mirrors 106 a and 106 b, three liquid crystal display elements108R, 108G, and 108B, a dichroic prism 110, an optical path deflectionelement 2, a projection lens system 112, and a relay lens 114.Hereinafter, the configuration of each unit will be described in detail.

An optical configuration of the projector 1 will be described.

Examples of the light source 102 include a halogen lamp, a mercury lamp,a light-emitting diode (LED). A light source exiting white light is usedas the light source 102.

Each of the three mirrors 104 a, 104 b, and 104 c has a function ofconverting an optical path inside the projector 1 through reflection.

On the other hand, each of the two dichroic mirrors 106 a and 106 b hasa function of separating white light exiting from the light source 102into the three primary colors of R (red), G (green), and B (blue) andguiding the separated light to the mutually different liquid crystaldisplay elements 108R, 108G, and 108B.

For example, the dichroic mirror 106 a has a function of transmittingthe light with a wavelength band of R and reflecting the light withwavelength bands of G and B in the white light. On the other hand, thedichroic mirror 106 b has a function of transmitting the light with thewavelength band of B in the light with the wavelength bands of G and Breflected from the dichroic mirror 106 a and reflecting the light withthe wavelength band of G.

Through the reflection by the dichroic mirrors 106 a and 106 b, thelength of the optical path of the light with the wavelength band of B islonger than the lengths of the optical paths of the other light.Accordingly, by providing a relay lens 114 in a midway point of theoptical path of the wavelength band of B, deviation in the optical pathis corrected.

Each of the liquid crystal display elements 108R, 108G, and 108B is usedas a spatial optical modulator. The liquid crystal display elements108R, 108G, and 108B are transmissive spatial optical modulatorscorresponding to the primary colors of R, G, and B, respectively,include, for example, pixels arrayed in a matrix form of vertical 1080rows and horizontal 1920 columns. In the pixels, the optical amount oftransmitted light with respect to incident light is adjusted and anoptical amount distribution of all the pixels in the liquid crystaldisplay elements 108R, 108G, and 108B is cooperatively controlled.

In the liquid crystal display elements 108R, 108G, and 108B, scanninglines and data lines are provided in correspondence to the pixels (notillustrated). Liquid crystal is disposed between pixel electrodes and acommon electrode disposed to face the pixel electrodes in correspondenceto positions at which the scanning lines and the data lines intersecteach other (not illustrated).

In addition to these elements, polarizing plates (not illustrated) areprovided in the liquid crystal display elements 108R, 108G, and 108B.When voltages of the data lines are applied to the pixel electrodesthrough selection of the scanning lines, liquid crystal molecules areoriented and the transmitted light is polarized. By appropriatelysetting the polarization by the liquid crystal molecules and thedisposition of the polarizing plates, the optical amount of transmittedlight can be adjusted for each pixel.

The light spatially modulated by the liquid crystal display elements108R, 108G, and 108B is incident on the dichroic prism 110 in threedirections. Of the incident light, the light with the wavelength bandsof R and B is refracted at 90° and exits. On the other hand, the lightwith the wavelength band of G goes straightly and exits. As a result,the light exiting from the dichroic prism 110 includes a full-colorimage in which images from the primary colors of R, G, and B aresynthesized, and the full-color image is incident on the optical pathdeflection element 2.

The optical path deflection element 2 will be described in detail below.The optical path deflection element 2 includes an optical member and canappropriately select whether the light incident on the optical member isdeflected (shifted).

The light transmitted through the optical path deflection element 2 isincident on the projection lens system 112.

The projection lens system 112 is a compound lens system in which aplurality of lenses are combined. An image synthesized in the compoundlens system 112 is enlarged and projected to a screen 8.

Next, an electric configuration of the projector 1 will be described.

The projector 1 according to the embodiment includes a control circuit120 and an image signal processing circuit 122 in addition to theoptical path deflection element 2 and the liquid crystal displayelements 108R, 108G, and 108B described above.

The control circuit 120 controls an operation of writing data signals tothe liquid crystal display elements 108R, 108G and 108B, an optical pathdeflection operation in the optical path deflection element 2, and anoperation of generating the data signals in the image signal processingcircuit 122.

The image signal processing circuit 122 has a function of separating animage signal Vid supplied from an external apparatus (not illustrated)for each of the three primary colors of R (red), G (green), and B (blue)and converting the image signal Vid into data signals Rv, Gv and Byproper for operations of the liquid crystal display elements 108R, 108G,and 108B. The converted data signals Rv, Gv, and By are supplied to theliquid crystal display elements 108R, 108G, and 108B, respectively, andthe liquid crystal display elements 108R, 108G, and 108B operate basedon the data signals Rv, Gv, and Bv.

Structure of Optical Path Deflection Element

As illustrated in FIGS. 3 to 5, the optical path deflection element 2includes an optical portion 202 that deflects light, a frame-shapedmovable portion 204 that supports the edge of the optical portion 202, ashaft portion 206 that supports the movable portion 204 so that themovable portion 204 is oscillatable, and a fixing portion 208 to whichthe shaft portion 206 is connected.

Of these portions, the optical portion 202 is configured to beoscillated using the shaft portion 206 as an oscillation shaft so that aposture of the optical portion 202 is changed. With the change in theposture of the optical portion 202, an exit direction of the lighttransmitted through the optical portion 202 can be changed (the positionof an optical path can be changed). Thus, the images combined in thedichroic prism 110 can be deflected (shifted) in any direction.

In the following description, the optical portion 202, the movableportion 204, the shaft portion 206, and the fixing portion 208 describedabove are collectively referred to as functional portions 200.

The optical path deflection element 2 further includes a casing 220 thatholds the entire optical path deflection element 2 and is used to fixthe optical path deflection element 2 to the inside of the projector 1and a casing fitting portion 224 (support portion) that is interposedbetween the casing 220 and the optical path deflection element 2 tomutually fix the casing 220 and the optical path deflection element 2.

As illustrated in FIGS. 3 and 4, the optical path deflection element 2includes a driving portion 230 that drives the optical portion 202 sothat the optical portion 202 is oscillated. The optical portion 202 isoscillated by a driving force generated by the driving portion 230.

Hereinafter, the configuration of each portion of the optical pathdeflection element 2 will be described in detail.

Functional Portions

Each of the functional portions 200 will be described.

The optical portion 202 according to the embodiment is configured as aplate-shaped body having a light transmission property, and thus platesurfaces (main surfaces facing each other) of the plate-shaped bodyfunction as light incident surfaces. According to an incident angle ofthe light, the light incident on the light incident surfaces of theoptical portion 202 is transmitted while going straight through theoptical portion 202 or is transmitted while being refracted (spatiallymodulated). Thus, by changing the posture of the optical portion 202 sothat a target incident angle is formed, it is possible to control adeflection direction or a deflection amount of the transmitted light.

In the embodiment, the front surface of the optical portion 202 servesas a light incident surface and the rear surface thereof serves as alight exit surface, but the incident direction of the light is notparticularly limited.

Examples of the material of the optical portion 202 include, forexample, various crystal materials such as crystal and sapphire, variousglass materials such as borosilicate glass (crown glass, super whiteglass, and Tempax (registered trademark)), lead glass (flint glass), andquartz glass, and various resin materials such as a polycarbonate-basedresin and an acrylic-based resin. Of these materials, an inorganic basedmaterial is preferably used. According to an inorganic based material,the elastic modulus of the optical portion 202 is large. In other words,rigidity thereof is large. Therefore, deflection irregularity of animage deflected in the optical portion 202 is suppressed.

The optical portion 202 according to the embodiment is formed in arectangular shape (square shape) in a plan view, as illustrated in FIG.5. The size of the optical portion 202 in a plan view is setappropriately so that a light beam exiting from the dichroic prism 110can be transmitted. In FIG. 5 and the other drawings, the verticaldirection is referred to as the Y axis direction and the horizontaldirection is referred to as the X axis direction. The leading side of anarrow indicating the X axis is referred to as a + (positive) side and abase side thereof is referred to as a − (negative) side.

The frame-shaped movable portion 204 is provided to surround the edge ofthe optical portion 202. The movable portion 204 is preferably formed ofa material with a smaller elastic modulus than the material of theoptical portion 202. By forming the movable portion 204 of thismaterial, it is possible to suppress stress occurring with oscillationfrom leading to unnecessary vibration of the optical portion 202 itselfto the minimum. That is, the movable portion 204 with the smallerelastic modulus surrounds the edge of the optical portion 202.Therefore, when the posture of the optical portion 202 is changed, thestress occurring in the optical portion 202 can be suppressed small, andthus unnecessary vibration occurring in the optical portion 202 itselfwith a stress distribution can be suppressed small. As a result, it ispossible to prevent an image deflected by the optical portion 202 frombeing deflected in an unintentional direction.

The movable portion 204 includes two movable portions 204X extending inthe X axis direction and two movable portions 204Y extending in the Yaxis direction. Accordingly, in the optical portion 202 formed in therectangular shape in a plan view, edged parallel in the X axis directionare supported by the movable portions 204X and edges parallel in the Yaxis direction are supported by the movable portions 204Y.

In a plan view, a fixing portion 208 is formed on the outer side of eachmovable portion 204Y, that is, on the opposite side of each movableportion 204Y to the optical portion 202 via a void portion 205. Thefixing portion 208 is formed in a frame shape surrounding the movableportions 204 via the void portion 205.

The fixing portion 208 includes two fixing portions 208X extending inthe X axis direction and two fixing portions 208Y extending in the Yaxis direction.

Each fixing portion 208X and each fixing portion 208Y are connected toeach other at each end. That is, the end of one fixing portion 208Y isconnected to one end of each fixing portion 208X and the end of theother fixing portion 208Y is connected to the other end of each fixingportion 208X. Thus, the fixing portions 208X and the fixing portions208Y are connected in a frame shape.

Of the two movable portions 204X, the end on the +X side of the movableportion 204X located on the +Y side of the optical portion 202 isconnected to the fixing portion 208Y mutually adjacent to this end viathe shaft portion 206. The shaft portion 206 is disposed over the voidportion 205, and thus the movable portion 204 is supported with respectto the fixing portion 208Y by the shaft portion 206.

On the other hand, of the two movable portions 204X, the end on the −Xside of the movable portion 204X located on the −Y side of the opticalportion 202 is connected to the fixing portion 208Y mutually adjacent tothis end via the shaft portion 206. The shaft portion 206 is disposedacross the void portion 205, and thus the movable portion 204 issupported with respect to the fixing portion 208Y by the shaft portion206.

As described above, the movable portions 204 and the fixing portions 208are connected via the two shaft portions 206.

Since the two shaft portions 206 can be twisted, the two shaft portions206 are disposed on an oscillation axis A when the movable portions 204are oscillated. That is, the oscillation axis A is set to be oblique tothe outer edge of the optical portion 202 formed in the rectangularshape in a plan view (in both sides of the X and Y axes). By oscillatingthe movable portions 204 along the oscillation axis A, it is possible tochange the posture of the optical portion 202 and control a deflectiondirection or a deflection amount of the light transmitted through theoptical portion 202.

Here, FIG. 6 is a partially enlarged perspective view illustrating thefunctional portions illustrated in FIG. 4. In FIG. 6, a part of thedriving portion is not illustrated.

As illustrated in FIG. 6, the shaft portion 206 is a portion that isprovided across the void portion 205 separating the movable portion 204Xfrom the fixing portion 208Y. In the shaft portion 206, a side surface2061 facing the void portion 205 is formed in as curved shape, asillustrated in FIG. 6. Thus, when the movable portions 204 areoscillated along the oscillation axis A, it is possible to preventstress from being concentrated locally in the shaft portion 206. As aresult, it is possible to prevent the characteristics of the shaftportion 206 from deteriorating.

The movable portions 204, the shaft portions 206, and the fixingportions 208 may be formed by adhering the separate portions to eachother, but are preferably integrated. Thus, it is possible to improveshock resistance or long-term durability of connection portions betweenthe movable portions 204 and the shaft portions 206 or connectionportions between the fixing portions 208 and the shaft portions 206.

As in the movable portion 204, each of the shaft portions 206 and thefixing portions 208 is preferably formed of a material with a smallerelastic modulus than the material of the optical portion 202(hereinafter shortly referred to as a “low elastic modulus material”)and is specifically formed of a resin material. Thus, a twistableproperty (a nature in which the shaft portions can be twisted) is givento the shaft portions 206 and a flexible property (a nature in which thefixing portions are flexible) is given to the fixing portions 208. As aresult, the optical portion 202 and the movable portions 204 can beoscillated at a sufficient oscillation angle mainly about theoscillation axis A.

On the other hand, functions of suppressing deformation and preciselytransferring a driving force generated by the driving portion 230 to theentire movable portions 204 are given to the optical portion 202.Therefore, a displacement amount at the time of the oscillation of theoptical portion 202 and the movable portions 204 is stabilized, and thusit is possible to deflect the light transmitted through the opticalportion 202 in a target deflection direction or by a target amount.

In particular, a resin material is preferable as the low elastic modulusmaterial. Since a resin material has relatively large elasticity, theresin material contributes to attenuation of unnecessary vibrationoccurring in the optical portion 202 due to the oscillation. That is, byforming the movable portions 204 of a resin material, it is possible tosuppress unnecessary vibration of the optical portion 202 generatedbased on a distribution of stress occurring due to the oscillation to besmall. As a result, it is possible to prevent the light deflected by theoptical portion 202 from being deflected in an unintended direction.

Examples of the resin material include polyethylene, polypropylene,silicon, polyacetal, polyamide, polycarbonate, polyphenylene ether,polyethylene terephthalate, polybutylene terephthalate, polyarylate,polysulphone, polyether sulfone, polyphenylene sulfide, polyether etherketone, polyimide, polyetherimide, and fluororesin. A material includingat least one thereof is used.

A tensile elastic modulus (Young's modulus) of the low elastic modulusmaterial may be less than the elastic modulus of the material of theoptical portion 202 and is preferably set within a predetermined range.

When the tensile elastic modulus of the low elastic modulus material isassumed to be 1, the tensile elastic modulus of the material of theoptical portion 202 is preferably 7 or more, is more preferably 10 ormore and less than 40, and is further more preferably 26 or more andless than 31. By appropriately selecting the material of the opticalportion 202 and the low elastic modulus material so that a ratio of thetensile elastic modulus is within the foregoing range, it is possible tocause oscillation easiness of the optical portion 202 and stability ofthe displacement amount at the time of the oscillation to be compatible.That is, when a ratio of the tensile elastic modulus of the material ofthe optical portion 202 to the tensile elastic modulus of the lowelastic modulus material is less than the foregoing lower limit value,the rigidity of the optical portion 202 is not sufficient depending onan oscillation condition. Therefore, the driving force generated by thedriving portion 230 is easily attenuated or the tensile elastic modulusof the low elastic modulus material is relatively larger, it isdifficult to twist the shaft portions 206, and thus there is a concernof the displacement amount at the time of the oscillation being small.Conversely, when the ratio of the tensile elastic modulus of thematerial of the optical portion 202 to the tensile elastic modulus ofthe low elastic modulus material is greater than the foregoing upperlimit value, the tensile elastic modulus of the low elastic modulusmaterial is relatively small depending on an oscillation condition, andthus there is a concern of the durability of the shaft portions 206being deteriorating.

For example, the tensile elastic modulus of the low elastic modulusmaterial is preferably about 0.1 GPa or more and about 10 GPa or lessand is more preferably about 0.5 GPa or more and about 7 GPa or less. Bysetting the tensile elastic modulus of the low elastic modulus materialwithin the foregoing range, it is possible to realize the shaft portions206 with an excellent twistable property and it is possible to realizethe movable portions 204 with given rigidity with which the posture ofthe optical portion 202 can be maintained while suppressing an influenceof the force of gravity. When this material is applied to the fixingportion 208, a sufficient flexible property can be given. Therefore,warping can be sufficiently realized in at least a thickness direction,and thus the fixing portions 208 capable of alleviating stressconcentration can be accordingly realized.

For example, the tensile elastic modulus of the material of the opticalportion 202 is preferably about 20 GPa or more and about 1000 GPa orless, and is more preferably about 30 GPa or more and about 200 GPa orless. By setting the tensile elastic modulus of the material of theoptical portion 202 within the foregoing range, it is possible tosuppress the deformation of the optical portion 202 and preciselytransfer the driving force generated by the driving portion 230 to theentire movable portions 204. Therefore, the displacement amount at thetime of the oscillation of the optical portion 202 is stabilized, andthus the light transmitted through the optical portion 202 can bedeflected in a target direction or can be deflected by a target amount.

A pixel group that forms an image deflected by the optical portion 202is a pixel collective in which columns of pixels arrayed in parallel tothe X axis are arrayed along the Y axis. That is, the pixel group isdisposed in a matrix form on the XY plane. The number of pixels is notparticularly limited, but is considered to be 1920 lines in the X axisdirection and 1080 lines in the Y axis direction.

The image (pixel group) in which the pixels are disposed in the matrixform is deflected when the image is transmitted through the opticalportion 202. However, as described above, when the oscillation axis A ofthe optical portion 202 is obliquely inclined with respect to both ofthe X and Y axes, a deflection direction of the image is also orientedin the oblique direction to both of the X and Y axes. Thus, for example,when an image projected to the screen 8 has a rectangular shape, theimage can be shifted obliquely with respect to both of the vertical andhorizontal sides. As a result, since the vertical and horizontalresolutions of the image can be substantially increased, for example,the projected image can be realized with a high resolution withoutincreasing the number of pixels of the liquid crystal display elements108R, 108G, and 108B.

The two shaft portions 206 are preferably disposed at positions at whicha point symmetry relation is satisfied with respect to the center of theoptical portion 202 at a plan view. Thus, since balance of theoscillation becomes good and the optical portion 202 can be stablyoscillated, a deflection behavior of an image is also stable. As aresult, an image with a high resolution can be stably projected.

The movable portions 204 according to the embodiment are configured tosurround the entire edge of the optical portion 202, but may notnecessarily surround the entire edge of the optical portion 202. Forexample, a part of the edge may be lost.

Here, FIG. 7 is a partially enlarged perspective view illustrating thefunctional portions illustrated in FIG. 4 when viewed from the frontsurface side. FIG. 8 is a cut sectional view illustrating the functionalportions when cut along an oscillation axis A of FIG. 7. In thefollowing description, a length in the vertical direction (that is, thenormal line direction of the light incident surface of the opticalportion 202) of FIG. 8 is referred to as a “thickness.”

When the functional portions 200 illustrated in FIG. 4 are viewed fromthe opposite side to the rear surface illustrated in FIG. 4, that is,the front surface, a front surface 208 a of a portion supporting theshaft portion 206 in the fixing portion 208Y protrudes toward the mostfront surface side in the functional portions 200, as illustrated inFIG. 7. On the other hand, in the embodiment, the rear surfaces of thefunctional portions 200 are flat surfaces. Therefore, in the fixingportion 208Y, the thickness of a portion corresponding to the frontsurface 208 a is thickest. Accordingly, since the thickness of thefixing portion 208Y corresponding to the front surface 208 a is large,the fixing portion 208Y easily functions as a fixing end of the shaftportion 206 for an oscillation motion of the movable portion 204, andthus a resonant frequency of the oscillation can be set to be high. Whenthe resonant frequency is high, a response speed of the optical pathdeflection element 2 is high, and thus high image quality can beachieved.

Of the front surface of the fixing portion 208Y, a front surface 208 bmutually adjacent to the side of the fixing portion 208X of the frontsurface 208 a described above is inclined to be closer to the rearsurface side, as the front surface 208 b is more distant from the frontsurface 208 a from the front surface 208 a to the fixing portion 208X.The thickness of the fixing portion 208Y gradually decreases accordingly(see FIG. 7).

The fixing portion 208X includes a first portion 208Xa and a secondportion 208Xb located outside the first portion 208Xa, that is, on aside more distant from the oscillation axis A than the first portion208Xa. The above-described inclined front surface 208 b continues withthe front surface of the first portion 208Xa.

On the other hand, of the front surface of the fixing portion 208Y, afront surface 208 c mutually adjacent to the opposite side to the fixingportion 208X illustrated in FIG. 7 (mutually adjacent to the frontsurface 208 a of FIG. 7 on the +Y side) is located on the rear surfaceside rather than the front surface 208 a and is configured such that thethickness of the fixing portion 208Y decreases. A stepped difference isformed between the front surfaces 208 a and 208 c.

As the result of such a configuration, the thickness of the fixingportion 208Y decreases continuously or stepwise as the fixing portion208Y is more distant from the front surface 208 a of the portionsupporting the shaft portion 206 in the Y axis direction (in theextension direction of the fixing portion 208Y).

Incidentally, FIG. 8 illustrates a cut sectional surface when the fixingportion 208Y and the shaft portion 206 and the like connected to thefixing portion 208Y are cut along the oscillation axis A (see FIG. 7) inthe thickness direction.

Since the movable portion 204 itself oscillates, the thickness of themovable portion 204 is less than that of the fixing portion 208Y. Thus,reduction in the mass is achieved, and thus the movable portion 204 canbe easily oscillated even with a smaller driving force.

The thickness of the shaft portion 206 is also less than that of thefixing portion 208Y. Thus, the shaft portion 206 is more easily twisted,and thus a sufficient oscillation displacement amount can be ensuredeven with a smaller driving force.

On the other hand, the fixing portion 208Y is configured such that thecross-sectional surface (a cut sectional surface of a surface orthogonalin the extension direction) has a shape elongate in the thicknessdirection. That is, the shape of the cross-sectional surface of thefixing portion 208Y is an elongate shape with a major axis in thethickness direction. The end of the fixing portion 208Y on the frontsurface side is connected to the shaft portion 206, as illustrated inFIG. 8. This portion is referred to as a “shaft portion connectionportion 208 d.”

On the other hand, the end of the fixing portion 208Y on the rearsurface side is not connected to the shaft portion 206 and serves as afree end, as illustrated in FIG. 8. This portion is referred to as a“free end portion 208 e.”

Here, when a driving force is given to the fixing portion 208Y by thedriving portion 230, the shaft portion 206 is oscillated to be twisted.As an angle (oscillation angle) at which the shaft portion 206 istwisted increases, the driving force is also spread to the fixingportion 208Y. As described above, since the thickness of the fixingportion 208Y is set to be greater than the thickness of the shaftportion 206 and a part of the fixing portion 208Y in the thicknessdirection serves as the free end portion 208 e, the driving forcespeared to the fixing portion 208Y displaces the fixing portion 208Y inthe thickness direction (the vertical direction of FIG. 8) or the X axisdirection (the horizontal direction of FIG. 8). As a result, compared toa case in which the fixing portion 208Y is not displaced, that is, aflexible property is not given to the fixing portion 208Y, local stressconcentration in the fixing portion 208Y is alleviated, and thusdeterioration in the characteristics of the functional portions 200caused due to the stress concentration can be suppressed. The fixingportion 208Y according to the embodiment is displaced in the thicknessdirection and the free end portion 208 e is also displaced in thehorizontal direction of FIG. 8, thereby contributing to the alleviationof the stress concentration.

By alleviating the stress concentration in the shaft portion 206 or thefixing portion 208Y, an improvement in durability at the time of addinga shock to the functional portions 200, that is, shock resistance, canbe achieved. This is because a width in which stress newly occurring dueto a shock can be allowed can be enlarged as the result obtained byachieving the reduction in the stress occurring in the shaft portion 206or the fixing portion 208Y. As a result, it is possible to obtain theprojector 1 with high reliability.

By alleviating the stress concentration in the shaft portion 206 or thefixing portion 208Y, it is possible to suppress the deterioration in thedriving characteristics of the functional portions 200 even when thetemperature of the functional portions 200 increases. This is also aneffect obtained because the allowable width of thermal stress occurringwith the increase in the temperature is enlarged with the achievement ofthe reduction in the stress occurring in the shaft portion 206 or thefixing portion 208Y.

Of the fixing portion 208Y, the thickness of the portion supporting theshaft portion 206 is greater than the thickness of the portion adjacentto this portion. Therefore, it is possible to ensure a largerdisplacement amount when the free end portion 208 e is displaced. Thatis, the fixing portion 208Y has not only the function of supporting theshaft portion 206 but also a function of a “beam” oscillating themovable portion 204. Therefore, the free end portion 208 e can bedisplaced more greatly, and thus the alleviation width of stressoccurring inside the fixing portion 208Y can be accordingly furtherenlarged.

By displacing the fixing portion 208Y actively, as described above, withthe twisting of the shaft portion 206, it is possible to compensate foran oscillation angle of the shaft portion 206. That is, by deforming thefixing portion 208Y even when the oscillation angle of the shaft portion206 itself is not set to be large, the oscillation angle can beaccordingly set to be large in all of the functional portions 200.

In FIG. 8, the movable portion 204 is formed to cover a part of thefront surface of the optical portion 202, but the connection of theoptical portion 202 and the movable portion 204 is not limited to theform illustrated in FIG. 8. For example, a connection form may beconfigured such that a side surface (a surface connecting the frontsurface to the rear surface) of the optical portion 202 and a sidesurface (a surface connecting the front surface to the rear surface) ofthe movable portion 204 face each other.

Here, FIGS. 9 and 10 are diagrams illustrating a simulation of adisplacement state when the functional portions illustrated in FIG. 4are oscillated about the oscillation axis A. In FIGS. 9 and 10, adisplacement amount in the oscillation is illustrated in an emphasismanner. FIGS. 9 and 10 are different from each other in the position ofa viewpoint when illustrated.

As illustrated in FIGS. 9 and 10, the optical portion 202 and themovable portions 204 are oscillated about the oscillation axis A passingthe shaft portions 206 while maintaining the shapes thereof. At thistime, as indicated by an arrow Bin FIG. 9, the free end portion 208 e ofthe fixing portion 208Y is displaced to be curved to the left side ofFIG. 9. Similarly, the free end portion 208 e of the fixing portion 208Yin a portion indicated by an arrow C is displaced to be curved to theleft side of FIG. 9.

As indicated by an arrow D, displacement of the free end portion 208 eof the fixing portion 208Y in the thickness direction (the upper side inthe portion indicated by the arrow D illustrated in FIG. 10) isillustrated in FIG. 10. In this way, by deforming the free end portion208 e, it is possible to compensate for the oscillation angle of theshaft portion 206. As a result, as described above, even when the shaftportion 206 is short and it is difficult to ensure a oscillation angle,a sufficient oscillation angle can be ensured in all of the functionalportions 200.

In other words, when the fixing portion 208Y cannot be displaced, asdescribed above, (for example, when the entire fixing portion 208Y isfixed), a necessary displacement amount is necessarily supplied withonly the shaft portion 206. In this case, in order not to increase thestress occurring in the shaft portion 206 too much, the length of theshaft portion 206 is set to be sufficiently long. However, when theshaft portion 206 is too long, the functional portions 200 may increasein size. Further, a problem may arise in that the projector 1 increasesin size.

Conversely, when the fixing portion 208Y can be displaced, as describedabove, a sufficient oscillation angle is ensured even when the shaftportion 206 is short. Thus, the shaft portion 206 can be shortened whilesuppressing an increase in stress. Further, the functional portions 200and the projector 1 can be miniaturized.

Of the fixing portion 208Y, a side surface 208 f facing the side of theoptical portion 202 is oblique to the front surface and the rear surfaceof the fixing portion 208Y, as illustrated in FIGS. 6 and 8. That is,the side surface 208 f of the fixing portion 208Y is an oblique surfaceoblique so that the length of the side surface 208 f in the X axisdirection gradually increases from the side of the free end portion 208e to the side of the shaft portion connection portion 208 d. In such aconfiguration, stress rarely concentrates on a connection portionbetween the fixing portion 208Y and the shaft portion 206, and thus itis possible to suppress deterioration in the characteristics of thefixing portion 208Y or the shaft portion 206.

A length L1 of the shaft portion 206 in the X axis direction isappropriately set according to the sizes of the functional portions 200and is not particularly limited. The length L1 is preferably about 0.2mm or more and about 5 mm or less and is more preferably about 0.5 mm ormore and about 3 mm or less.

On the other hand, a thickness t1 of the shaft portion 206 isappropriately set according to the sizes of the functional portions 200.The thickness t1 is preferably about 0.5 mm or more and about 7 mm orless and is more preferably about 1 mm or more and about 5 mm or less.

A ratio L1/t1 of the length L1 to the thickness t1 of the shaft portion206 is preferably about 0.2 or more and about 3 or less, is morepreferably about 0.3 or more and about 1 or less, and is further morepreferably about 0.4 or more and about 0.8 or less. Thus, it is possibleto obtain the shaft portion 206 with an excellent twistable propertywhile suppressing deterioration in the mechanical characteristics of theshaft portion 206.

The side surface 208 f of the fixing portion 208Y may continue with arear surface 2062 of the shaft portion 206. However, as illustrated inFIGS. 6 and 8, a step 208 g formed along the fixing portion 208Y ispreferably formed between the side surface 208 f of the fixing portion208Y and the rear surface 2062 of the shaft portion 206. By forming sucha step 208 g, stress rarely concentrates due to connection of the fixingportion 208Y and the shaft portion 206. The step 208 g is a surfaceparallel to the rear surface of the fixing portion 208Y and is the samesurface as the rear surface 2062 of the shaft portion 206.

A length L2 of the step 208 g in the X axis direction is appropriatelyset according to the sizes of the functional portions 200 and is notparticularly limited. The length L2 is preferably about 0.03 mm or moreand about 2 mm or less and is more preferably about 0.1 mm or more andabout 1 mm or less. By setting the length L2 within the foregoing range,it is possible to alleviate the stress concentration on the connectionportion of the fixing portion 208Y and the shaft portion 206.

A ratio L2/L1 of the length L2 of the step 208 g to the length L1 of theshaft portion 206 is preferably about 0.05 or more and about 0.8 or lessand is more preferably about 0.1 or more and about 0.5 or less.

A length L3 of the rear surface of the fixing portion 208Y in the X axisdirection is also appropriately set according to the sizes of thefunctional portions 200 and is not particularly limited. The length L3is preferably about 0.3 mm or more and about 5 mm or less and is morepreferably about 0.5 mm or more and about 2 mm or less.

A maximum thickness t2 of the fixing portion 208Y is also appropriatelyset according to the sizes of the functional portions 200. The maximumthickness t2 is preferably about 2 mm or more and about 10 mm or lessand is more preferably about 3 mm or more and about 7 mm or less.

A ratio L3/t2 of the length L3 to the maximum thickness t2 of the fixingportion 208Y is preferably about 0.05 or more and about 0.8 or less andis more preferably about 0.1 or more and about 0.5 or less. Thus, asufficient displacement amount is given to the free end portion 208 e ofthe fixing portion 208Y. As a result, it is possible to particularlyalleviate local stress concentration in the fixing portion 208Y andincrease the oscillation angle of the shaft portion 206 more easily.

When an entire length of the functional portions 200 in the Y axisdirection illustrated in FIG. 5 is assumed to be L4, although the entirelength L4 is not particularly limited, for example, the entire length L4is preferably about 20 mm or more and about 150 mm or less and is morepreferably about 40 mm or more and about 90 mm or less.

Each of lengths L5 and L6 illustrated in FIG. 5 is not particularlylimited, and is preferably about 10 mm or more and about 80 mm or lessand is more preferably about 20 mm or more and about 65 mm or less.

Each of lengths L7 and L8 illustrated in FIG. 5 is not particularlylimited, and is preferably about 5 mm or more and about 70 mm or lessand is more preferably about 10 mm or more and about 60 mm or less. Aratio L7/L8 of the length L7 to the length L8 is appropriately setaccording to, for example, an aspect ratio of the liquid crystal displayelements 108R, 108G, and 108B.

A length L9 illustrated in FIG. 5 is not particularly limited, and ispreferably about 3 mm or more and about 40 mm or less and is morepreferably about 5 mm or more and about 30 mm or less.

A length L10 illustrated in FIG. 5 is not particularly limited, and ispreferably about 10 mm or more and about 80 mm or less and is morepreferably about 20 mm or more and about 60 mm or less.

As illustrated in FIG. 7, a height t3 of a step difference between thefront surface 208 a of the fixing portion 208Y and the front surface 208c adjacent to the front surface 208 a is not particularly limited, andis preferably about 0.1 mm or more and about 2 mm or less and is morepreferably about 0.2 mm or more and about 1 mm or less.

Casing

The casing 220 includes a bottom portion 221 having a flat plate shapeand two leg portions 222 standing from the edges of the bottom portion221.

The bottom portion 221 is formed in a rectangular shape in a plan viewand is located on the front surface side of the functional portions 200described above.

The leg portions 222 are convex sections standing from the edges of twosides facing each other among four sides of the bottom portion 221. Thefunctional portions 200 are placed to be interposed between the two legportions 222.

Although not illustrated, an open hole is formed in the bottom portion221 so that the light transmitted through the optical portion 202 canpass through the open hole. Thus, propagation of the light deflected bythe optical portion 202 is prevented from being obstructed by the bottomportion 221.

When the bottom portion 221 has translucency, the above-described openhole may not be necessary.

A material of the casing 220 is not particularly limited. For example, ametal material such as aluminum can be used.

A casing fitting portion 224 (support portion) mechanically connects thecasing 220 to the functional portions 200. The casing fitting portion224 illustrated in FIG. 3 includes a frame portion 225 that has a frameshape in a plan view and an extension portion 226 that is formed byextending a part of the frame portion 225 outward (outside the frameportion 225).

Parts of the frame portion 225 are configured to be mechanicallyconnected to the fixing portions 208X of the functional portions 200. Onthe other hand, the extension portion 226 is mechanically connected tothe leg portions 222 of the casing 220 described above. Vibrationdamping members (not illustrated) such as vibration damping washers maybe provided between the frame portion 225 and the fixing portions 208Xor between the extension portion 226 and the leg portions 222 tomechanically connect each portion. Thus, it is possible to rarelytransfer vibration at the time of the oscillation of the functionalportions 200 to the casing 220. The fixing portion 208X may bemechanically connected directly to any spot of the casing 220 withoutproviding the casing fitting portion 224. Even in this case, vibrationdamping members may be provided between the fixing portions 208X and thecasing 220 to mechanically connect therebetween.

In this way, since the functional portions 200 are fixed to the casing220 in the fixing portions 208X, it is possible to avoid direct fixingof the fixing portions 208Y to the casing 220. Thus, the fixing portions208Y can be displaced with a sufficient displacement amount, asdescribed above, and thus the optical portion 202 can be oscillated at anecessary oscillation angle without causing local stress concentration.

A method of fixing the functional portions 200 to the casing 220 is notlimited to the method using the above-described casing fitting portion224. For example, the casing fitting portion 224 may be omitted and thefunctional portions 200 may be directly fixed to the casing 220.

The method of connecting the functional portions 200 to the casingfitting portion 224 and the method of connecting the casing fittingportion 224 to the casing 220 are not particularly limited. For example,a method using a connection tool such as a screw or a method using anadhesive or an adhesion tape can be used.

The fixing portions 208 according to the embodiment are formed in theframe shape, but are not limited to such a shape. Any shape may be usedas long as the shape can support the shaft portions 206.

The optical portion 202 and the movable portions 204 may be adheredaccording to any method, but are adhered via, for example, an adhesive.Examples of the adhesive include an epoxy-based adhesive, anacrylic-based adhesive, and a silicon-based adhesive.

Driving Portion

Next, the driving portion 230 will be described.

The driving portion 230 according to the embodiment includes a magnet232 that is fixed to the rear surface of one of the two movable portions204X, a circular coil 234 that is fixed to the fixing portion 208X, anda coil fitting portion 236 that is interposed between the coil 234 andthe fixing portion 208X and fits the coil 234 to the fixing portion208X.

The magnet 232 is configured as, for example, a permanent magnet. Byfixing the magnet 232 to the movable portion 204X, a magnetic field canbe generated, and thus a driving force can be generated for the movableportion 204X through magnetic interaction along with a magnetic fieldgenerated from the coil 234.

Examples of the permanent magnet include a neodymium (FeNdB) magnet, aferrite magnet, a samarium-cobalt magnet, an alnico magnet, and aFeCo-based magnet.

The coil 234 is formed in a circular shape and is configured as, forexample, a layered winding coil, and a voice coil. The coil 234 may bean air-core coil or may include any core.

One surface of the coil 234 is fixed to the coil fitting portion 236.Thus, magnetic interaction is generated between the magnet 232 and thecoil 234, and thus a driving force is generated in the magnet 232. Apredetermined gap is formed between the magnet 232 and the coil 234 sothat the movable portion 204 including the magnet 232 can be oscillatedby the driving force.

In the driving portion 230 according to the embodiment, a so-calledmoving magnet type electromagnetic actuator scheme in which a magnetside is oscillated is adopted. However, the driving scheme is notparticularly limited and the driving portion 230 may have a so-calledmoving coil type driving scheme of oscillating a coil side.

FIG. 11A is a plan view schematically illustrating the movable portion204 and the magnet 232 fixed to the movable portion 204. FIG. 11B is aside view schematically illustrating the magnet 232 illustrated in FIG.11A and the coil 234 provided to correspond to the magnet 232.

When a voltage is applied to the coil 234 illustrated in FIG. 11B, aforce driving the magnet 232 upward or downward in FIG. 11B is generatedin accordance with an application direction of the voltage and adirection of the magnetic field generated from the magnet 232. Forexample, when the N pole and the S pole are generated, as illustrated inFIG. 11B, the magnet 232 can be driven so the magnet 232 approaches thecoil 234.

The driving portion 230 illustrated in FIGS. 11A and 11B is the drivingportion according to the embodiment. The driving portions 230illustrated in FIGS. 11C to 11H are different configuration examples ofthe driving portion 230 in which the electromagnetic actuator scheme isapplied.

The driving portion 230 illustrated in FIGS. 11A and 11B is a drivingportion of a type in which the magnet 232 and the coil 234 are disposedasymmetrically with respect to the oscillation axis A and which isdriven by adding a moment to the movable portion 204 (axis asymmetrymoment type).

On the other hand, the driving portion 230 illustrated in FIGS. 11C and11D is the same as the driving portion 230 illustrated in FIGS. 11A and11B from the viewpoint of typing called axis asymmetry moment type, butdiffers in that the disposition of the magnet 232 in the movable portion204 differs. That is, in the driving portion 230 illustrated in FIGS.11C and 11D, the magnet 232 is disposed at a position which is mostdistant from the oscillation axis A in the movable portion 204. Thus,the movable portion 204 can be easily driven even with a small magneticforce.

In the driving portion 230 illustrated in FIGS. 11E and 11F, thepositions of the N pole and the S pole of the magnet 232 differ fromthose of the moment type driving portion 230 so that lines of magneticforce are radiated in parallel to a plane direction of the movableportion 204. In the coil 234, the direction of the coil 234 also differsfrom that of the moment type driving portion 230 so that the windingaxis is parallel to the plane direction of the movable portion 204. Evenwhen the magnet 232 and the coil 234 are disposed in this way, a drivingforce can be given to the magnet 232 (axis asymmetry torque type). Thecoil 234 including a winding wire 2341 and a core 2342 is preferablyused.

On the other hand, the driving portion 230 illustrated in FIGS. 11G and11H is the same as the driving portion 230 illustrated in FIGS. 11E and11F from the viewpoint of typing called a torque type, but differs inthat the disposition of the magnet 232 in the movable portion 204differs. That is, in the driving portion 230 illustrated in FIGS. 11Gand 11H, the magnet 232 is disposed so that line symmetry is satisfiedfor the oscillation axis A in the movable portion 204. Thus, there isthe advantage in which a driving frequency is easily increased (axissymmetry torque type).

The driving scheme for the driving portion 230 is not limited to theabove-described schemes, but a piezoelectric driving scheme or otherdriving schemes may be used.

The position of the driving portion 230 or the number of drivingportions 230 is not limited to the illustrated position or number. Forexample, the plurality of driving portions 230 may correspond to onemoving portion 204.

The size of the driving portion 230 is not particularly limited. Forexample, when the magnet 232 has the rectangular shape illustrated inFIG. 5, the length of the shorter side is preferably about 1 mm or moreand about 10 mm or less and the length of the longer side is preferablyabout 5 mm or more and about 30 mm or less.

Operation of Optical Path Deflection Element

Next, an operation of the optical path deflection element 2 will bedescribed. The operation of the optical path deflection element 2 may bethe same as the operation described in, for example, JP-A-2012-013766.

FIGS. 12 and 13 are diagrams illustrating a principle in which theoptical path deflection element illustrated in FIG. 3 deflects light.

When no voltage is applied to the coil 234, the optical portion 202 isnot oscillated in the optical path deflection element 2. Therefore, asindicated by a dotted line in FIG. 12, an incident angle of light 81which is incident on the optical portion 202 is a right angle, and thusthe light 81 becomes straight light 82 without refraction to be exited.

Conversely, when a predetermined voltage is applied to the coil 234, theoptical portion 202 is oblique, for example, as indicated by a solidline in FIG. 12, the light 81 incident on the optical portion 202 inthis state is refracted when transmitted through the optical portion202, and then becomes light 83 to be exited. Since the light 83 isdeviated from the light 82 in a space, an image formed by the light 83is projected to the screen 8 in a state in which the image is deviatedfrom an image formed by the light 82.

FIG. 13 illustrates images 84 and 85 in which pixels of 4 vertical rowsand 4 horizontal columns are disposed in a matrix form. The image 84 isa collective of pixels 841 formed by the light 82 illustrated in FIG. 12and the image 85 is a collective of pixels 851 formed by the light 83illustrated in FIG. 12.

FIG. 13 illustrates an example in which the image 84 is shifted to theimage 85 by oscillating the optical portion 202. At this time, a shiftamount is half of the pitch of the pixel 841. As a result, the number ofpixels of the image 85 projected to the screen 8 is twice the number ofpixels of the image 84, and thus a high resolution of the image isachieved.

As described above, the image 85 is shifted obliquely in the arraydirection of the pixels 841. Therefore, the number of pixels of theimage 85 is substantially twice in the vertical and horizontal sides.

A shift amount of the image shifted by the optical path deflectionelement 2 is not limited to the half of the pitch of the pixel, but maybe, for example, ¼ or ⅛.

Second Embodiment

Next, an optical path deflection element to which a second embodiment ofthe optical device according to the invention is applied will bedescribed.

FIG. 14 is a diagram illustrating a principle in which the optical pathdeflection element to which the second embodiment of the optical deviceaccording to the invention is applied deflects light. In FIG. 14, thesame reference numerals are given to the same configurations as those ofthe above-described embodiment.

An optical path deflection element 2 according to the embodiment is thesame as the optical path deflection element 2 according to the firstembodiment except for a difference in the principle in which an opticalportion 202 deflects light.

That is, the optical portion 202 according to the embodiment has a lightreflection property, and thus this point differs from the firstembodiment in which the optical portion has light transmission property.

When no voltage is applied to the coil 234, the optical portion 202 isnot oscillated in the optical path deflection element 2. Therefore, asindicated by a dotted line in FIG. 14, light 81 incident on the opticalportion 202 is reflected as light 82 indicated by a dotted line.

Conversely, when a predetermined voltage is applied to the coil 234, theoptical portion 202 is oblique, for example, as indicated by a solidline in FIG. 14. When the optical portion 202 is oblique, an incidentangle of the light 81 that is incident on the optical portion 202 and anexit angle of the light 81 are changed. Therefore, the light 81 isreflected as light 83 indicated by a solid line. Accordingly, bychanging the posture of the optical portion 202 so that a targetincident angle is achieved, it is possible to control a deflectiondirection or a deflection amount of the light 83 (reflected light).Since the light 83 is deviated from the light 82 in a space, an imageformed by the light 83 is projected to the screen 8 in a state in whichthe image is deviated from an image formed by the light 82. As a result,a projector including the optical path deflection element 2 has the sameadvantage as the projector according to the first embodiment.

The material of the optical portion 202 according to the embodiment isnot particularly limited as long as the material has the lightreflection property. For example, a member in which a reflection film isattached to a material exemplified as the material of the opticalportion 202 according to the first embodiment can be exemplified inaddition to a material having gloss, such as silicon or metal.

Even in the above-described second embodiment, it is possible to obtainthe same operations and advantages as those of the first embodiment.

Third Embodiment

Next, an optical scanner to which a third embodiment of the opticaldevice according to the invention is applied and a projector to whichthe third embodiment of the image display apparatus according to theinvention is applied will be described.

FIG. 15 is a diagram illustrating an optical configuration of theprojector to which the third embodiment of the image display apparatusaccording to the invention is applied. In FIG. 15, the same referencenumerals are given to the same configurations as those of theabove-described embodiment.

A projector 9 according to the embodiment is a scanning type projectorthat forms an image by scanning light and is the same as the projector 1according to the first embodiment except that an optical scanner 94 towhich the third embodiment of the optical device according to theinvention is applied is included.

That is, the projector 9 according to the embodiment includes a lightsource device 91 that emits light such as laser, a cross dichroic prism92, an optical scanner 93 that serves to perform main scanning, anoptical scanner 94 (the third embodiment of the optical device accordingto the invention) that serves to perform sub-scanning, and a fixedmirror 95.

A light source device 91 illustrated in FIG. 15 includes a red lightsource device 911 that radiates red light, a blue light source device912 that radiates blue light, and a green light source device 913 thatradiates green light.

The cross dichroic prism 92 is configured such that four right-angleprisms are bonded and is an optical element that combines the lightradiated from the red light source device 911, the blue light sourcedevice 912, and the green light source device 913.

The projector 9 is configured such that light is radiated from each ofthe red light source device 911, the blue light source device 912, andthe green light source device 913 based on image information from a hostcomputer (not illustrated), the light is combined by the cross dichroicprism 92, the combined light is allowed to scan by the optical scanners93 and 94, the light is reflected by the fixed mirror 95, and a colorimage is formed on the screen 8.

Here, the optical scanning of the optical scanners 93 and 94 will bedescribed specifically.

The light combined by the cross dichroic prism 92 is allowed to scan inthe horizontal direction by the optical scanner 93 (main scanning). Thelight allowed to scan in the horizontal direction is further allowed toscan in the vertical direction by the optical scanner 94 (sub-scanning).Thus, a two-dimensional color image can be formed on the screen 8. Byusing the optical device according to the invention as the opticalscanner 94, excellent drawing characteristics can be exerted.

In the optical scanner 94, an optical path can be deflected while thelight is reflected in the optical portion 202. As a result, a highresolution can be realized.

However, the invention is not limited to the projector 9 as long as thelight is allowed to scan by the optical scanners 93 and 94 and an imageis formed to a target object. For example, the fixed mirror 95 may beomitted.

The optical device according to the invention may also be applied to theoptical scanner 93.

Even in the above-described third embodiment, it is possible to obtainthe same operations and advantages as those of the first and secondembodiments.

Fourth Embodiment

Next, a head-mounted display to which a fourth embodiment of the imagedisplay apparatus according to the invention is applied will bedescribed.

FIG. 16 is a perspective view illustrating the head-mounted display towhich the fourth embodiment of the image display apparatus according tothe invention is applied. In FIG. 16, the same reference numerals aregiven to the same configurations as those of the above-describedembodiment.

A head-mounted display 300 illustrated in FIG. 16 includes glasses 310and a video output unit 90 mounted on the glasses 310. The video outputunit 90 has the same configuration as the projector 9 according to thethird embodiment. The video output unit 90 displays a predeterminedimage viewed with one eye on a display unit 320 provided in a site whichis originally a lens of the glasses 310.

The display unit 320 may be transparent or opaque. When the display unit320 is transparent, information from the video output unit 90 can beoverlapped on information from the real world to be used.

Two video output units 90 may be provided in the head-mounted display300 so that images viewed with both eyes are displayed on two displayunits.

Even in the above-described fourth embodiment, it is possible to obtainthe same operations and advantages as those of the first to thirdembodiments.

The optical device and the image display apparatus according to theinvention have been described according to the illustrated embodiments,but the invention is not limited thereto. For example, in the opticaldevice and the image display apparatus according to the invention, theconfiguration of each unit can be substituted with any configurationwith the same function and any optional configuration can also be added.

In the invention, two or more configurations (features) may be combinedin each of the foregoing embodiments.

The optical device according to the invention can also be applied to,for example, a light switch or a light attenuator in addition to theoptical path deflection element.

The image display apparatus according to the invention can also beapplied to a printer and a head-up display (HUD) in addition to aprojector or a head-mounted display (HMD).

The entire disclosure of Japanese Patent Application No. 2014-223706filed Oct. 31, 2014 is expressly incorporated by reference herein.

What is claimed is:
 1. An optical device comprising: an optical portionthat has a light incident surface on which light is incident; a movableportion that supports the optical portion; a shaft portion that supportsthe movable portion so that the movable portion is oscillatable; and afixing portion that is connected to the shaft portion, wherein thefixing portion has a thickness greater than the shaft portion andincludes a portion of which an end not connected to the shaft portionserves as a free end, and wherein an elastic modulus of each of themovable portion, the shaft portion, and the fixing portion is smallerthan an elastic modulus of the optical portion.
 2. The optical deviceaccording to claim 1, further comprising: a permanent magnet that isprovided in the movable portion; and a coil that generates a magneticfield to be operated to the permanent magnet.
 3. The optical deviceaccording to claim 1, further comprising: a support portion thatsupports the fixing portion, wherein the support portion supports thefixing portion at a position at which the portion serving as the freeend is excluded.
 4. An image display apparatus comprising: the opticaldevice according to claim
 3. 5. The image display apparatus according toclaim 4, wherein a position of a pixel displayed by radiating the lightis shifted by changing an optical path of light exiting from the opticaldevice in the optical device.
 6. The optical device according to claim1, wherein each of the movable portion, the shaft portion, and thefixing portion is formed of a resin material.
 7. The optical deviceaccording to claim 1, wherein in the fixing portion, a thickness of aportion connected to the shaft portion is thicker than a thickness of aportion mutually adjacent to the portion connected to the shaft portion.8. An image display apparatus comprising: the optical device accordingto claim
 7. 9. The image display apparatus according to claim 8, whereina position of a pixel displayed by radiating the light is shifted bychanging an optical path of light exiting from the optical device in theoptical device.
 10. The optical device according to claim 1, wherein theoptical portion transmits light.
 11. The optical device according toclaim 1, wherein the optical portion reflects light.
 12. An imagedisplay apparatus comprising: the optical device according to claim 1.13. The image display apparatus according to claim 12, wherein aposition of a pixel displayed by radiating the light is shifted bychanging an optical path of light exiting from the optical device in theoptical device.
 14. The image display apparatus according to claim 12,wherein the optical device allows the light to scan to form an image.15. An optical device comprising: an optical portion that has a lightincident surface on which light is incident; a movable portion thatsupports the optical portion; a shaft portion that supports the movableportion so that the movable portion is oscillatable; and a fixingportion that is connected to the shaft portion, wherein the fixingportion has a thickness greater than the shaft portion and includes aportion of which an end not connected to the shaft portion serves as afree end, and wherein each of the movable portion, the shaft portion,and the fixing portion is formed of a resin material.